Headaches are one of the most common ailments, and afflict millions of individuals. The specific etiology of headaches may be difficult to pinpoint. Known sources of headache pain include trauma and vascular, neurovascular, autoimmune, degenerative, infectious, drug and medication-induced, inflammatory (sarcoid), neoplastic (primary or metastatic), metabolic-endocrine, iatrogenic (such as post-surgical), muscloskeletal and myofascial causes. Even if the condition underlying the headache pain is identified and treated, headache pain may persist.
Headaches have traditionally been treated with medications to prevent their recurrence and to alleviate acute pain and associated symptoms, such as nausea and vomiting. Non-invasive modalities of migraine treatment, which may be used alone or in combination, have included: diet modification, which may include the avoidance of known headache triggers (such as certain foods); biofeedback and relaxation techniques as well as other psychological modalities; acupuncture; chiropractic manipulation; and physical therapy. Anesthetic agents (such as Lidocaine) have been applied to the sphenopalatine ganglia, either directly, using a syringe, or indirectly, by soaking a long cotton swab in the anesthetic and placing the swab intranasally adjacent to the sphenopalatine ganglia, such that the anesthetic diffuses through the nasal mucosa to affect the sphenopalatine ganglia. Invasive approaches for the treatment of cluster headaches have included localized anesthetic block, surgical resection, radiofrequency, alcohol/phenol infiltration, radiosurgery and cryotherapy of the sphenopalatine ganglia and the trigeminal nerve and ganglion.
Newer techniques for treating a variety of neurological disorders have included electrical stimulation of cranial nerves of the central nervous system, such as the sphenopalatine ganglion, glossopharangeal, vagus, or trigeminal nerves. The principle behind these approaches is to disrupt or modulate abnormal neuronal transmissions in the nervous system through the application of the modulating electrical signals. However, surgical implantation of neurostimulator electrodes on or proximate a target cranial nerve can be difficult and typically relies on patient response to electrical stimulation (i.e., reporting of tingling, buzzing, vibratory sensation or pain) to determine which cranial nerve the implant is positioned on.
Thus, there is a need in the implantable medical devices field for a method of accurately positioning a neurostimulator electrode on a cranial nerve of the central nervous system, including the nerves of the sphenopalatine ganglion, maxillary nerve, and vidian nerve. Such improvements may significantly increase implantation accuracy and success rates, and reduce surgical implantation time and patient discomfort.